In recent years, there has been an increasing number of surgeons using surgical staples, rather than conventional sutures, for closing surgical incisions. In part, this is because the use of surgical staples and surgical stapling instruments has made many previously difficult surgical procedures much simpler to perform. Of more importance, however, is that the use of surgical staples significantly reduces the time required for performing most surgical procedures, and therefore reduces the length of time during which the patient must be maintained under anesthetic. Many types of surgical stapling instruments have been devised for different surgical procedures. An added benefit of certain surgical stapling instruments is their ability to be used fluoroscopically or endoscopically, reducing the size of the incision, the amount of patient discomfort, and the amount of recovery time.
The present invention is directed to a surgical instrument for applying surgical fasteners to internal organs and tissues such as the lung, esophagus, stomach, duodenum, and intestines. The invention is embodied in a linear surgical stapler which permits access to restricted surgical sites, e.g., the thoracic region and the pelvic area of the human body.
In its earliest form, the linear surgical stapling instrument was a permanent, multi-use instrument, and the surgical staples were manually loaded into the instrument one at a time.
A subsequent improvement in linear surgical stapling instruments was the development of presterilized, disposable loading units or staple cartridges.
Several types of surgical fastener applying instruments are known for applying surgical fasteners to body tissue clamped between relatively movable fastener holding and anvil portions of the instrument. The surgical fasteners may be metal staples as shown, for example, in U.S. Pat. 3,275,211, or consist of non-metallic resinous materials as shown, for example, in U.S. Pat. 4,402,445. In the case of metal staples, the staple legs are typically driven through the tissue and formed by an anvil to secure the staples in the tissue. In the case of non-metallic fasteners, each fastener may initially consist of two separate parts, i.e., a fastener part disposed in the fastener holding part of the apparatus, and a retainer part disposed in the anvil part of the apparatus. The leg or legs of the fastener parts are driven through the tissue and interlock with the retainer parts to secure the fasteners in the tissue. Although most surgical staples are biologically inert and remain permanently in the body, biologically absorbable metal surgical staples are known. Surgical fasteners of non-metallic resinous materials can also be made either biologically absorbable or non-absorbable.
The surgical instrument of the present invention is not limited to use with any particular type or form of fasteners. The various surgical fasteners mentioned above represent examples of the types of fasteners which can be used with the instrument of the present invention. Thus, as used herein, "surgical fastener" is a term which is generic to all of the above types of fasteners. Similarly, as used herein, "fastener holder" and "anvil" are terms which, except for certain improvements described hereinafter, are generic to surgical instruments for applying all of the above types of fasteners.
In the prior instruments for applying surgical fasteners to tissue clamped between the fastener holding and anvil portions of the instrument, a distal fastener applying assembly is rigidly connected to the proximal actuator portion of the instrument. More recently, however, there has been increasing interest in instruments in which the connection between the fastener applying assembly and the actuator assembly is not completely rigid.
Also, in view of rising hospital costs, there has been an ever-increasing interest in disposable surgical stapling instruments to eliminate as much work as possible, i.e., disassembly, cleaning, reassembly, sterilization and the like, and to be more efficient, while at the same time, not having to compromise the surgical procedures.